Photodiode

Vehicle to vehicle data transmission, we present initial designs and results of a small-scale prototype using light fidelity (Li-Fi) technology, a new technology that was developed in the last few years, which still needs more systematic inquiry on its sustainability for outdoor vehicular networks. Vehicle to vehicle communication is the most effective solution we have used in order to reduce vehicle's accidents. The propose use of Li-Fi technology comprises mainly light-emitting diode (LED) bulbs as means of connectivity by sending data through light spectrum as an optical wireless medium for signal propagation. In fact, the usage of light emitting diode (LED) eliminates the need of complex wireless networks and protocols. The design system is aim to ensure a highly-reliable communication between a commercial LED-based transaction light and a receiver mount on a vehicle.

Integrated circuit manufacturing capabilities have reached the stage where it is technically and economically feasible to create new components that may be monolithically combined with them to create unique devices. One of the most elementary yet reliable of such monolithic components is the elevated diode. These diodes may be used to detect or generate light for parallel photodetection or photogeneration applications, such as imaging, chemical detection, or displays. Because new materials are required for all implementations, various process flows and integration challenges are discussed. In particular, focus on interconnection to the top and bottom of the junction is considered. In addition, since the elevated diode concept gives the designer control of such parameters as junction thickness, semiconductor bandgap, and light emission spectrum, the issues that drive junction design are presented for both the elevated photodiode and elevated OLED. Finally, because of the decoupling of diode size and pixel size, and the presence of new materials, novel pixel circuits are considered to achieve novel or greater pixel-level functionality, and because material behaviour may dictate the method to drive the junction. The new possibilities that these junctions present create a new realm of applications and are initial examples of a new class of devices called monolithic instruments.

The flame distance sensor is designed to use when open flaming fres occur. It responds to the light emitted by flame during combustion. The detector discriminates between flame and other light sources by responding only to particular optical wavelengths. The physical quantity that can be used as a reference for determining the distance of the flame is the intensity of radiation emitted by the flame. Intensity of radiation can be measured by the photodiode output, when the photodiode receives the radiation. In this research, the writers propose to develop a new prototype of simple, low-cost flame sensing device using a photodiode. The photodiode is integrated with an infrared flter, which is made of black flm inside the floppy disk, to block certain wavelengths other than infrared. The photodiode is operated in photoconductive mode, where a positive regulated DC power supply is connected to the cathode. The anode is connected to the output terminal and a resistor that acts as a voltage divid...

GaInP-GaAs heterojunction bipolar phototransistors grown by metal organic vapor phase epitaxy (MOVPE) and operated with frontside optical injection through the emitter are reported with high optical gain (< 88) and record high frequency performance (28 GHz). ...

Hydrogenated amorphous silicon (a-Si:H) holds the promise of realizing three-dimensional semiconductor inte- grated circuits by placing the photodiode above the pixel control circuitry rather than in-plane with it. This has the obvious advantages of enabling large die-size reduction and higher light collection efficiency compared to standard crystalline silicon arrays. We have developed a photodiode array technology that is fully compatible with 0.35 lm CMOS process flows to produce image sensors arrays with 10-bit dynamic range that are 30% smaller than comparable standardcrystallinesiliconphotodiodes.Thesesensorshave50%highersensitivity,andtwotimeslowerdarkcurrent when compared to bulk silicon sensors of the same design. The various methods of interconnection of the diode to the array and their advantages will be presented. Diode leakage currents as low as 30 pA=cm2 have been measured. The effectofdopedlayerthicknessandconcentrationonquantumefficiency(ashighas80%around560nm),andtheeffect of a-Si:H defect concentration on diode performance will be discussed. Ó 2002 Elsevier Science B.V. All rights reserved.

ABSTRACT The particular Cd0.7 Hg0.3Te band structure:almost equality of band gap and spin orbit splitting, provides good ionization properties to this alloy : a high ionization coefficients ratio is expected. The devices elaboration is made by planar technology. A N+/N/P+ structure is achieved by ions implantation followed by a diffusion process. A diffused guard ring allows to avoid surface and junction edge effects. The I (V) characteristic shows a breakdown voltage (VB) of about 100 V. The dark current at 0.95 VB, amounts 100nA.Photodiodes sensitivity is typiclly of 0.7. A/W when M=1.Multiplication coefficients as high as 40 have been measured, the photoresponse spatial homogeneity in gain mode has been also controlled with a lOμm size spot : no microplasma effect have been observed. Photodetectors sensitivity, measured at 500 MHz, remains identical in avalanche operating mode. Good linearity is obtained when plotting P-N schottky noise versus light intensity No excess noise was observed. The study of the avalanche photodiode noise, synchronous with 1.3. μm DEL emission, at 30 MHz with a 1 MHz bandwith has been carried out in relation to the multiplication factor, and has led to an estimation of the ionization coefficient ratio.

Selective degeneration of the retinal photoreceptor layers underlies blindness in retinitis pigmentosa (RP) and other inherited retinal disorders. Because there are no therapies for these patients, we are evaluating the possibility that electrical stimulation delivered to the subretinal space by a microphotodiode array (MPA) could replace, in some aspect, the function of diseased photoreceptors. Early MPA prototypes utilized gold as the electrode material, which gradually dissolved during the postoperative period following subretinal implantation. Here we present the results obtained when different MPA materials were used. Semiconductor-based silicon MPAs (2 mm in diameter; 50 microm in thickness), incorporating iridium/iridium oxide (IrOx) or platinum (Pt) electrodes, were implanted into the subretinal space of the right eye of normal cats with the use of vitreoretinal surgical techniques. Indirect ophthalmoscopy, fundus photography, ganzfeld electroretinography, and histology were...

Copper phthalocyanine (CuPc)/n-silicon junction was fabricated using thermal evaporator method. X-ray
analysis of the CuPc film confirms the β-phase with preferred orientation along (100) direction. The crystallite size of the
CuPc film was estimated using XRD data and observed to be about 12.6 nm. The current-voltage characteristics of
Au/CuPc/n-Si/Au device was studied in dark and under illumination. The device showed diode characteristics. The diode
parameters such as ideality factor, barrier height and series resistance were determined using different techniques such
as conventional forward bias I-V characteristics, Cheung method and Norde’s function. A good agreement between the
diode parameters calculated form these methods was observed. The analysis of the diode characteristics confirmed that
the transport mechanism of the Au/CuPc/n-Si/Au diode at the higher electric fields was governed by the space-chargelimited currents. The photoconducting behavior of the diode suggests that it can be used as a photosensor in optoelectronic applications